KR20170036227A - Electrode Assembly Having Supporting Member for Holding of Electrode - Google Patents

Abstract

The present invention relates to an electrode assembly, comprising unit cells composed of a pole plate laminate having a structure, in which separation members are disposed between pole plates composed of a positive electrode or a negative electrode. Provided is an electrode assembly, wherein the unit cells have electrode terminals having a protruding structure in the direction of one side or both sides, and the separation members have relatively larger sizes than the positive electrode and the negative electrode, while a pole plate support part is coated on a remaining part excluding an inner part, on which the pole plate is located in the separation members.

Description

[0001] Electrode Assembly Having Supporting Member for Electrode [0002]

The present invention relates to an electrode assembly comprising an electrode support.

2. Description of the Related Art As technology development and demand for mobile devices have increased, the demand for secondary batteries as energy sources has been rapidly increasing, and a lot of research has been conducted on secondary batteries that can meet various demands.

Typically, from the viewpoint of the shape of the secondary battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery that can be applied to products such as cellular phones with a small thickness, and a high energy density, a discharge voltage, There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

In addition, the secondary battery is classified according to the structure of the anode assembly, the cathode assembly, and the electrode assembly having the separator structure sandwiched between the anode assembly and the cathode assembly. Typically, (Stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in a unit of a predetermined size are sequentially stacked with a separator interposed therebetween, a jelly-roll (wound type) electrode assembly having a structure A stack-folding type electrode assembly in which unit cells such as a bi-cell or a full cell stacked with a separator interposed between the positive and negative electrodes of a unit are wound.

Figures 1 and 2 schematically illustrate an exemplary structure and fabrication of such a stack / foldable electrode assembly.

Referring to these drawings, a plurality of pull cells 10, 11, 12, 13, 14, ... each having a positive electrode / separator / negative electrode laminated sequentially as unit cells are superimposed, Respectively. The separating film 20 has a unit length that can wrap around the pull cell and is bent inward for each unit length and starts from the center pull cell 10 and continues from the outermost pull cell 14 to each of the pull cells, Respectively. The distal end of the separation film 20 is thermally fused or bonded with an adhesive tape 25 or the like.

Such a stack-folding type electrode assembly can be obtained by arranging the pull cells 10, 11, 12, 13, 14 ... on a long length of the separation film 20 and separating the separation films 20 at one end 21 ) And then winding them sequentially.

The first pull cell 10 and the second pull cell 11 are located at a distance separated by a width corresponding to at least one pull cell, The lower surface electrode of the first pull cell 10 is brought into contact with the upper surface electrode of the second pull cell 11 after the outer surface of the first pull cell 10 is completely coated with the separation film 20.

In the case of pull cells or bi-cells used as unit cells, the anode / separator / cathode is manufactured through a lamination process. In order to facilitate the manufacturing process, a gap between the electrodes and the separator is designed differently In this structure, when a physical impact is applied in the z-axis direction with respect to the plane of the battery cell, there is a possibility that short-circuit occurs in the gap between the electrodes and the separator.

In addition, the stack-folding type electrode assembly may suffer from damage to the separator due to various reasons such as negligence in operation or errors in the process of mounting on the separator film and winding, and in particular, Or in the case of the separator included in the bi-cells, the separation membrane located at the left and right gaps between the electrodes and the separation membrane may be folded during the winding process.

Furthermore, in the case of a stacked electrode assembly or a lamination-stacked electrode assembly as well as a general stack-folding electrode assembly, a separation membrane included in the unit cells may be shrunk due to heat, There is a problem that a part of the surface of the electrode is exposed from the separation membrane due to the shrinkage, and the electrode having the same polarity is brought into contact with the interface at the interface due to such defects.

Therefore, there is a high need for a technique capable of improving the capacity of a battery cell while fundamentally solving these problems.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

That is, an object of the present invention is to provide an electrode assembly that includes a unit cell having a structure in which an electrode support portion is coated on an outer surface except an inner surface portion where an electrode plate is located in a separation membrane, the force applied to the unit cells in the electrode assembly can be canceled by correcting the force applied to the unit cells inside the electrode assembly through the coated electrode plate support when the physical impact is applied in the z axis direction and the problem of short circuit due to membrane breakage or membrane shrinkage can be solved And to provide an electrode assembly having an effect of suppressing deterioration in performance of a battery.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an electrode assembly comprising unit cells formed of a laminate having a structure in which a separator is interposed between positive plates or negative plates,

Wherein the unit cells have a structure in which electrode terminals protrude in one direction or in both directions;

The separator has a relatively larger size than the positive electrode and the negative electrode, and the separator has a structure in which the electrode plate supports are coated on the outer side except the inner surface where the electrode plate is located.

Therefore, the electrode assembly according to the present invention includes the unit cells having the structure in which the electrode support portion is coated on the outer side except the inner surface portion where the electrode plate is located in the separation membrane, so that the plane of the electrode assembly The force applied to the unit cells in the electrode assembly can be compensated through the coated electrode plate support to cancel the force and the problems such as the occurrence of a short circuit due to the collapse of the separator or the shrinkage of the separator Thereby providing an effect of suppressing deterioration in performance of the battery.

The unit cells may be suitably applied to a unit cell having a stacked structure of a general anode / separator / cathode. For example, the unit cells may be full cells having polarities different from each other, And at least one negative electrode may be a bi-cell having polarities identical to each other in polarity plates disposed on both sides in a structure in which a separation membrane is interposed.

Meanwhile, in the electrode assembly, the electrode assembly may be applied to various structures such as a structure in which the unit cells are stacked or a structure in which the unit cells are wound. In one specific example, the electrode assembly may be formed such that unit cells composed of pull cells or bi- Stacked structure having a structure in which the layers are stacked in the height direction as a reference.

In another specific example, the electrode assembly may be a stack-folding structure of a structure in which unit cells are wound by one sheet-like separation film.

Meanwhile, as described above, in the case of pull cells or bi-cells, the anode / separator / cathode may be bonded through a lamination process. In order to facilitate the manufacturing process, the gap between the electrodes and the separator .

In one specific example, the separator may be designed to have a size ranging from 105% to 130% with respect to the positive electrode and the negative electrode. Specifically, And may have a structure with a largely extended size.

In such a structure, the electrode plate supporting portion may have a structure in which the electrode plates are coated on the left and right side surplus portions perpendicular to the direction in which the electrode terminals protrude from the unit cell, corresponding to the structure in which the separator extends.

In another specific example, the separator may have a structure in which the electrode terminal is protruded from the unit cell to a large extent. In such a structure, the electrode plate support portion may include a portion where the electrode terminal is located in a direction in which the electrode terminal protrudes The remaining portions may be coated on the remaining portions.

The electrode plate supporting portion is a structure capable of canceling a force applied to the unit cells in the electrode assembly when a physical impact is applied in the z-axis direction with respect to the plane of the electrode assembly. For example, It is preferable that the thickness corresponds to the thickness of the single electrode plate.

It is preferable that the electrode plate supporting portion includes a polymer resin as a material that does not affect the operation of the battery. Specifically, the polymer resin may include polyethylene terephthalate, polybutadiene, styrene resin, acrylic resin, And a blend resin. More specifically, the polymer resin may preferably be an ABS resin as a blend resin.

The electrode plate supporting part may be made of a polymer composite containing an organic or inorganic filler in a matrix of a polymer resin, but is not limited thereto.

On the other hand, the electrode plate supporting part is not particularly limited as a method of coating on the separation film to a predetermined thickness, and is formed on a separator by a 3D printer, a coating roller, or a nozzle, for example. It can be formed in a coated form.

The present invention also provides a battery cell in which the electrode assembly is embedded in a battery case.

For reference, the battery cell may be a lithium ion battery cell or a lithium ion polymer battery cell, and the battery cell may be composed of a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte solution containing a lithium salt.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The non-aqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride, etc. are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The present invention can also provide a device including one or more of the battery cells, wherein the device is a mobile phone, a wearable electronic device, a portable computer, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, , A plug-in hybrid electric vehicle, and a power storage device.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

As described above, according to the electrode assembly of the present invention, the electrode assembly includes the unit cells having the structure in which the electrode plate supporting part is coated on the outer side except the inner surface area where the electrode plate is located in the separation membrane, When a physical impact is applied in the z-axis direction with respect to the plane of the assembly, the force applied to the unit cells in the electrode assembly can be compensated through the coated electrode support to cancel the force, It is possible to provide an effect of suppressing the performance deterioration of the battery.

1 is a schematic diagram of an exemplary structure of a conventional stack-folding type electrode assembly;
FIG. 2 is a schematic diagram illustrating an exemplary arrangement of unit cells in a manufacturing process of the stack-folding type electrode assembly of FIG. 1; FIG.
3 is a schematic view of the structure of a lamination-stacked electrode assembly according to one embodiment of the present invention;
4 is a schematic view of a unit cell included in the electrode assembly of FIG. 3;
5 and 6 are schematic diagrams of unicells according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

FIG. 3 is a schematic view showing a structure of a lamination-stacked electrode assembly according to an embodiment of the present invention, and FIG. 4 is a schematic view of a structure of a unit cell included in the electrode assembly of FIG. 3 .

Referring to these drawings, an electrode assembly 100 according to the present invention includes unit cells 110 having a structure in which a separator 120 is interposed between electrode plates composed of an anode 111 and a cathode 112, In the height direction.

The unit cells 110 have a structure in which the electrode terminals 141 and 142 protrude in one direction and the separator 120 has a structure having a size of 120% with respect to the anode 111 and the cathode 112, Left and right lateral surplus portions perpendicular to the direction in which the terminals 141 and 142 protrude are formed.

Plate supporting portions 130 having a structure in which an ABS resin is coated by a 3D printer are formed on the residue except for the inner surface portion where the anode 111 and the cathode 112 are located in the separator 120, The thickness of the electrode plate supporting portion 130 is formed to have a thickness corresponding to the thickness of the single anode plate 111 or the cathode single plate 112.

As shown in FIG. 4, the electrode plate supporting part 130 is coated in a shape protruding in the z-axis direction with respect to the plane of the unit cell 110. The electrode plate supporting part 130 is coated on the separating film 120 on the upper and lower ends, Since the electrode assembly 100 is supported at the corresponding positions between the electrode plate supporting units 130, when a physical impact is applied in the z-axis direction with respect to the plane of the electrode assembly 100, You can offset the force.

Since the electrode plate supporting portion 130 is coated at both ends of the separator 120 with the thickness of the single electrode plate corresponding to the thickness of the anode 111 or the cathode 112, the structure in which the unit cells 110 are stacked in the height direction In the structure in which the separator 120 is shrunk due to the heat generated in the cell during operation of the battery, a short circuit due to shrinkage of the separator can be obtained. It is possible to provide an effect capable of suppressing the occurrence of the problem.

5 and 6 are schematic diagrams of unicells according to another embodiment of the present invention.

5, the unit cell 210 has a structure in which electrode terminals 241 and 242 are protruded in one direction. The separator 220 is formed in a structure in which the electrode terminals 141 and 142 are protruded, Surplus portions are formed in the remaining portions except the portions where the terminals 141 and 142 are located and left and right surplus portions perpendicular to the direction in which the electrode terminals 141 and 142 protrude are formed.

The thickness of the electrode plate supporting part 230 is formed to have a thickness corresponding to the thickness of the single electrode plate and the z-axis Direction to cancel the physical impact.

6, the unit cell 310 has a structure in which the electrode terminals 341 and 342 are protruded in one direction. The separator 320 has a structure in which the electrode terminals 141 and 142 protrude An excess portion is formed in the opposite direction and left and right surplus portions perpendicular to the direction in which the electrode terminals 141 and 142 protrude are formed.

5 and 6 illustrate that the electrode terminals are protruded in the same direction. However, the protruding direction of the electrode terminals may be different depending on the structure and the shape of the electrode assembly, It is also possible to change freely.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (19)

An electrode assembly comprising unit cells composed of a laminate of a structure in which a separator is interposed between and adhered to an electrode plate composed of an anode or a cathode,
Wherein the unit cells have a structure in which electrode terminals protrude in one direction or in both directions;
Wherein the separator has a relatively larger size than the positive electrode and the negative electrode, and the electrode plate support is coated on the outer side except the inner surface portion where the electrode plate is located in the separation membrane. The electrode assembly of claim 1, wherein the unit cells are pull cells having polarities different from each other. The unit cell according to claim 1, wherein the unit cells are formed of bi-cells having polarities identical to each other in polarity plates on both sides in a structure in which one or more positive electrodes and one or more negative electrodes are stacked with a separator interposed therebetween. Assembly. The electrode assembly according to claim 1, wherein the electrode assembly is a lamination-stack type structure in which unit cells are stacked in a height direction with respect to a plane. The electrode assembly according to claim 1, wherein the electrode assembly is a stack-folding structure of a structure in which unit cells are wound by one sheet-like separation film. The electrode assembly of claim 1, wherein the separation membrane has a size of between about 105% and about 130% of the size of the anode and the cathode. The electrode assembly according to claim 1, wherein the electrode plate supporting portions are coated on left and right side surplus portions perpendicular to the direction in which the electrode terminals protrude. The electrode assembly according to claim 1, wherein the electrode plate supporting portion is coated on remaining surplus portions except a portion where the electrode terminal is located in a direction in which the electrode terminal protrudes. The electrode assembly of claim 1, wherein the coating thickness of the electrode support is a thickness corresponding to the thickness of the anode or cathode single electrode. The electrode assembly of claim 1, wherein the electrode support comprises a polymeric resin. The electrode assembly according to claim 10, wherein the polymer resin is at least one selected from the group consisting of polyethylene terephthalate, polybutadiene, styrene resin, acrylic resin, rubber resin, and blend resin. 12. The electrode assembly according to claim 11, wherein the polymer resin is an ABS resin as a blend resin. 11. The electrode assembly of claim 10, wherein the electrode support comprises a polymer composite comprising an organic or inorganic filler in a matrix of polymer resin. The electrode assembly according to claim 1, wherein the electrode support is formed on the separator by a 3D printer, a coating roller, or a nozzle. A battery cell comprising an electrode assembly according to any one of claims 1 to 14 embedded in a battery case. The battery cell according to claim 15, wherein the battery cell is a lithium ion secondary battery or a lithium ion polymer secondary battery. A battery pack comprising at least one battery cell according to claim 15. A device comprising a battery pack according to claim 17. 19. The device of claim 18, wherein the device is selected from a cell phone, a wearable electronic device, a portable computer, a smart pad, a netbook, a LEV (Light Electronic Vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, Lt; / RTI &gt;

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